Device in sack sewing machines for separating the warp between the sacks



July 5, 1932. F. EBERT 1,865,893 DEVICE IN SACK SEWING MACHINES FOR SEPARATING THE WARP BETWEEN THE SACKS Filed July "1-5, 1930 4 Sheets-Sheet 1 lit nw III I I flm m July 5,1932. I EBERT 1,865,893

DEVICE IN SACK SEWING MACHINES FOR SEPARATING THE WARP BETWEEN THE SACKS Filed July 15, 1930 4 Sheets-Sheet 2 fig. 3. n H

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THE SACKS 4 Sheets-Sheei 3 i J P F. EBERT Filed July 15, 1930 July 5, 1932. DEVICE IN SACK SEWING mcnmms FOR SEPARATING was WARP BETWEEN July 5, 1932. EBERT 1,865,893

DEVICE IN SACK SEWING MACHINES FOR SEPARATING THE WARP BETWEEN THE SACKS Filed July 1.5, 1930 4 Sheets -Sheet 4 v E jrw/enzari' Patented July 5, 1932 UNITED STATES FFPATENT OFFICE,

FRITZ EBERT, OF OBERNDORF-ON-THE-NECKAR, GEEMANY DEVICE IN SACK SEWING MACHINES FOR SEPARA'IING THE WAR]? BETWEEN" THE SAGKS V Application filed July 15, 1930, Serial No. 468,180, and in Germany Ju1y.24, 1929.

The present invention relates to a device in sack sewing machines for separating the warp between the sacks.

The warp by means of which the filled sacks are continually sewn up by a machine is in the prevailing practice cut off between the sacks by attached scissors or star blades suffering from certain drawbacks.

The invention eliminates these drawbacks 113 by replacing the known warp cutting devices by a rotary circular knife of known type.

The employment of a circular knife for cutting off the warp involves considerable 15 practical and economic advantages. The economic side is of special importance, since the cost of sewing up the sacks must be reduced to a minimum.

For example, the rotary circular knife 26 effects the separation of the warp more rapidly than the existing devices, which not only saves time but also prevents the material to be sewn from accumulating. Furthermore, no time is lost in taking down or exchanging 25 the separating means, as an oilstone held against the cutting edge of the rotating circular knife will resharpen it in a very short time, and no special knowledge is required for carrying out this sharpening operation.

39 Thus the grinding outfit needed for the knives hitherto in use can be dispensed with also.

Moreover, a circular knife does not wear off rapidly so that regrinding with its resultant interruption of service is a rare occurrence and will require only a very short time.

The rotary circular knife is fixed in its location, that is, its shaft cannot move transversally or longitudinally, and the warp is separated by being guided against it. The cutting edge projects from a channel-like indentation in the table, the indentation ascending towards the sewing unit and opening towards the discharge side for the sacks.

The circular knife requires little driving power and can be driven directly from the sewing machine, but separate driving such as by motor afiords the advantage of rendering the knife independent of the speed of the machine, which, during the steps of separating the warp andfeeding a new sack, often runs slowly. I V

By way of example, embodiments of the inventions are illustrated in the accompanying drawings, in which Figure 1 is a front view of the cutting device; Figs. 2 and 3 are, respectively, a side and front view, partly in section,i;of the device driven by the sewing machine; and Figs. 4 and 5 are, respectively,

a side and front view of the device driven,

The cutting device employed for this pur pose according to the invention consists of the rotary circular knife 6, the warp 03 being pressed, for instance by hand, for a moment against the cutting edge of the knife and thus separated at the desired point.

For this purpose the table 7 contains an indentation g from which the cutting edge of the circular knife 6 projects and into which the warp d is pressed. The indentation g is preferably channel-like and extends on the.

side of the stitch-forming elements until it is flush with the surface of the table while it is open for the passage of the warp d on the discharge side for the sacks.

In the modification shown in Figs. 2 and 3 the circular knife 6 is driven by the machine and disposed on a horizontal shaft h which rotates in the bearings 71 of a bracket k screwed on to the machine 6 and which extends perpendicularly to the main drivingshaft Z of the sewing machine I), the rotation of which is transmitted by gearing, such as helical or worm gears m, to the shaft h and thus to the circular knife 6.

In the modification shown in Figs. 4 and 5 9 the circular knife 6 is driven by the electric motor n.

I claim 1. A sewing machine for closing filled sacks by sewing, comprising a sewing needle,-

a rotary circular knife whose center of rotation is stationary, for cutting the warp between successive sacks, means for rotating said knife, a table plate for said machine having a horizontal gutter-like groove behind the needle, arranged in the direction of movement of the sacks, the cutting edge of said knife entering into the said groove transversely to the longitudinal direction of the groove.

2. A sewing machine as in claim 1 wherein the groove is deepened in the direction of movement of the sacks, and is open in said direction at its end.

3. A sewing machine as in claim 1 wherein the means for rotating the rotary knife is the mechanism for operating the sewing machine itself.

4. A sewing machine as in claim l'wherein the means for rotating the rotary knife is a separate motor.

In testimony whereof I aflix my signature.

F. EBERT. 

